isequal violates transitive property

[glennmoy]

Bit of technicality but according to the docs for isequal

isequal is an equivalence relation - it is reflexive (=== implies isequal), symmetric (isequal(a, b) implies isequal(b, a))
and transitive (isequal(a, b) and isequal(b, c) implies isequal(a, c)).

but one can easily violate this last property in AxisKeys

julia> A = ones(3);

julia> KA1 = wrapdims(ones(3), 'a':'c');

julia> KA2 = wrapdims(ones(3), 'd':'f');

julia> isequal(A, KA1)
true

julia> isequal(A, KA2)
true

julia> isequal(KA1, KA2)
false

I guess isequal is overloaded to account for floats and missings when comparing the underlying arrays but it means we violate this property of the function when comparing between keyed arrays. I'm wondering if this is indeed intended behaviour or an oversight when overloading the function?

[mcabbott]

Almost certainly an oversight, sorry. (IIRC hash was also broken for quite a while.)